Optical time display device having intermittent drive

ABSTRACT

An optical time display device comprises a dial plate provided with a plurality of unit time display perforations arranged on a circle on one side of the dial plate, a source of light mounted on the opposite side of the dial plate at the center thereof. The source of light is enclosed by an opaque rotary cylinder provided with a radial opening and the light is successively transmitted to the unit time display openings by means of a bent light transmission member with one end fitted in the radial opening.

United States Patent 1191- 2,534,877 12/1950 Owen "Si 50R Ochiai et al. Jan. 8 1974 [54] OPTICAL TIME DISPLAY DEVICE HAVING 3,005,439 10/1961 Ellenwood 58/50 R INTERMITTENT DRIVE 3,486,322 12/1969 Abend 58/50 R 3,490,226 1/1970 Anderson... 58/50 R Inventors: Jiro Ochuu, Yokohama; Rlntaro 3,651,634 3/1972 Cooper 521/50 R Nishina, Yonezawa, both of Japan [73] Assignee: Tamura Electric Works, Ltd., Primary Har1d Pitts Tokyo, Japan r rC lttiek Thompson Pfund 22 F] d: M l l 1 972 57 ABSTRACT [21] P 255782 An optical time display device comprises a dial plate provided with a plurality of unit time display perfora- [30] Foreign Application Priority Data tions arranged on a circle on one side of the dial plate, May 25, 1971 Japan 46/41977 a Source ef-light mounted on the pp Side Of the dial plate at the center thereof. The source of light is 52 us. (:1. ss/so R, 340/380 R e o y h p q rotary cylinder Provided with a 58 Field of Search .00411/19/34; 58/50 R; radial Opening and the light is successively transmitted 1 to the unit time display openings by means of a bent [56] Ref Cit d I light transmission member with one end fitted in the UNITED STATES PATENTS 'radlal i 1 Claim, 2 Drawing Figures 4b aw ///4/,- r g Z l 3 Z.

. 6hf Bi! 4 2 3 5- j/ 1 OPTICAL TIME DISPLAY DEVICE HAVING INTERMITTENT DRIVE BACKGROUND OF THE INVENTION This invention relates to an optical time display device-wherein an elapsed time is displayed .by successively movinga light spot through a number of unit time display openings arranged on a circle on a dial plate of a clock.

According to a prior design of the optical time display device a plurality of light sources are disposed behind the plurality of perforations of the dial plate and the light sources are successively lighted. According to another design a single light source is rotated behind the perforated dial plate. However, the former design requires to provide a number of light sources thus .increasing the size and cost of the time display device. Moreover, as the light sources are flashed frequenty their life is shortened thereby increasing the cost of maintenance. In the latter design, it is necessary to provide sliding contacts in order to assure continuous supply of electric power to the rotating light source. This also complicates the construction.

SUMMARY OF THE INVENTION Accordingly, it is an object of this invention to provide an improved optical time display device of simple construction requiring only one lightsource and does not require any sliding contact for the light source.

According'to this invention, there is provided an optical time display device comprising a dial plate provided with a plurality of unit time display perforations arrangedon a circle on one side of the dial plate, a source of light mounted on the opposite side of the dial plate at the center thereof, an optical rotary cylinder enclosing the source of light, the opague rotary cylinder being provided with a radial opening, means for rotating the opaque rotary cylinder, and a bent light transmission member with one end fitted in the radial opening and the other end faced to the opposite side of the dial plate whereby the plurality of unit time display perforations'are successively illuminated by the light emanated from the source of light when the opaque rotary cylinder is rotated.

- BRIEF DESCRIPTION THE DRAWING DESCRIPTION OF. THE PREFERRED EMBODIMENT The optical time display device illustrated in the accompanying drawing comprises a shallow cupshaped dial plate 1 provided with a plurality of unit time display perforations which are arranged on the same circle. The dial plate 1 is fit in the opening of a cylindrical casing 10. In the illustrated example, the respective unit time display perforations 5 are graduated with digits indicating minutes or seconds. A recessed projection 6 for mounting a light source 2 is formed on the rear side of the dial plate 1 at the center thereof. The light source 2 is threaded in a socket 6a contained in the projection 6. The bottom of the socket 6a is connected to conductors 6b leading to a source of supply, not shown. A driving motor 7, preferably a synchronous motor is secured at the center of the bottom wall of the casing 10 for driving an opaque rotary clyinder 3 through a shaft 7a. The opaque rotary cylinder 3 has an inner diameter slightly larger than the outer diameter of the projection 6 so as to completely shield the light source 2. A letter L shaped light transmission member 4 consisting of a bundle of glass fibers or a rod of acrylic resin or the like is secured to a radial opening 3a in the side wall of the rotary cylinder 3 for transmitting the light emanated from the light source 2 successively to the time display perforations 5. It is tov be understood that the driving motor 7 can be substituted by a spring motor. The rotary drive for cylinder 3 or driving shaft 7a were provided with a suitable cam mechanism to intermittently rotate the light transmission member to the positions behind successive time display perforations for displaying respective unit times.

As shown by the arrows shown in FIG. 2, the driving motor 7 rotates the rotary cylinder 3 and the light transmission member 4 in the clockwise'direction. During this rotation, the light source 2 is constantly lighted so that the light emanated therefrom is projected towards the successive time display perforations through the end surface 4b of the light transmission member 4. According, when one views the display device from the lefthand side one will observe that a light spot passes successively through the time display perforations 5 as the time elapses. j I

Since the rotary light transmission element 4 successively transmits the light emanated from a single light lection of the diameter of the dial plate and the dimensource to a plurality of unit time display perforations arranged on the same circle on the dial plate of a clock, it is not necessary to provide a plurality of light sources or sliding contacts between a rotary light source and a source of supply as inthe prior art designs. Moreover, according to this invention atime display device of any desired size can be readily provided by the suitable sesion of the light transmission member. The time display device can be used as a common clock or a rough time display device for various games.

It should be understood that the invention is not limited to the particular embodiment shown and described and that many changes and modifications will be obvious to one skilled in the art without departing from the true spirit and scope of the invention as defined in the appended claims.

What is claimed is: I

1. An optical time display device comprising a dial plate provided with a plurality of unit time display perforat ions arranged on a circle on one side of said dial plate, a source of light mounted on the opposite side of said dial plate at the center thereof, an opaque rotary cylinder enclosing said source of light, said opaque rotary cylinder being provided with a radial opening,

means for rotating said opaque rotary cylinder intermittently to register with said perforations, and a bent light transmission member with one end fitted in said radial opening and the other end faced to the opposite side of said dial plate whereby said plurality of unit time display perforations are successively illuminated by the light emanated from said source of light when said opaque rotary cylinder is rotated. 

1. An optical time display device comprising a dial plate provided with a plurality of unit time display perforations arranged on a circle on one side of said dial plate, a source of light mounted on the opposite side of said dial plate at the center thereof, an opaque rotary cylinder enclosing said source of light, said opaque rotary cylinder being provided with a radial opening, means for rotating said opaque rotary cylinder intermittently to register with said perforations, and a bent light transmission member with one end fitted in said radial opening and the other end faced to the opposite side of said dial plate whereby said plurality of unit time display perforations are successively illuminated by the light emanated from said source of light when said opaque rotary cylinder is rotated. 